#include <iostream>
#include <list>

using namespace std;

class Graphss
{
    int V;
    list<int> *adj;

public:
    Graphss(int V)
    {
        this->V = V;
        adj = new list<int>[V];
    }

    void addEdge(int v, int w)
    {
        adj[v].push_back(w);
    }

    void BFS(int s)
    {
        bool *visited = new bool[V];
        for (int i = 0; i < V; i++)
            visited[i] = false;

        list<int> queue;

        visited[s] = true;
        queue.push_back(s);

        list<int>::iterator i;

        while (!queue.empty())
        {
            s = queue.front();
            cout << s << " ";
            queue.pop_front();
            for (i = adj[s].begin(); i != adj[s].end(); ++i)
            {
                if (!visited[*i])
                {
                    visited[*i] = true;
                    queue.push_back(*i);
                }
            }
        }
    }
};

int main()
{
    Graphss g(4);
    g.addEdge(0, 1);
    g.addEdge(0, 2);
    g.addEdge(1, 2);
    g.addEdge(2, 0);
    g.addEdge(2, 3);
    g.addEdge(3, 3);

    cout << "Following is Breadth First Traversal "
         << "(starting from vertex 2) \n";
    g.BFS(2);

    return 0;
}